A new family of transition-metal-contg. phosphates ANa3M7(PO4)6, where A = K, Rb, Cs and M = Mn, Fe, Co, was synthesized via high-temp. (650-800°), solid state reactions. Sizable single crystals up to 1 cm (∼160 mg) were grown for structure and property characterization. The extended structure comprises of alternating corner- and edge-sharing triangular chains of FeOn (n = 5,6) polyhedra involving four crystallog. distinct Fe(II) cations. The triangular chains propagate along the a and b directions to form slabs, which are interlinked by P5+ and a 5th Fe2+ cation to form the three-dimensional lattice. The magnetic susceptibility studies suggest that some of these fascinating compds. exhibit a ferromagnetic transition at temps. between 10K and 15K. The field-dependent studies on the oriented single crystal of RbNa3M7(PO4)6 show the occurrence of magnetization steps at 2-5K. The authors will 1st discuss some prior research developments relevant to the study of geometrically frustrated magnetic (GFM) interactions, followed by the results of the authors' exploratory synthesis in the pseuo-quaternary iron(II) phosphate system and finally some initial studies of temp.- and field-dependent magnetic properties.